The following quote from ACS Publications Inorganic Chemisty Journal is telling - The point here is that energy storage needed for solar Personalised Energy (PE) is currently within reach of the chemist with the design of catalysts that effectively promote eq 1 or 2 in the forward (solar storage) and reverse (fuel cell) directions.
Personalized energy (PE) is a transformative idea that provides a new modality for the planet’s energy future. By providing solar energy to the individual, an energy supply becomes secure and available to people of both legacy and nonlegacy worlds and minimally contributes to an increase in the anthropogenic level of carbon dioxide. Because PE will be possible only if solar energy is available 24 h a day, 7 days a week, the key enabler for solar PE is an inexpensive storage mechanism. HY (Y = halide or OH−) splitting is a fuel-forming reaction of sufficient energy density for large-scale solar storage. Read the full article